CUPC 8: adhoc group chat

I just deployed CUP/CUPC 8, this version of client is all new for me. I discovered that features like Persistent Chat Room and Archiving require an external database (postgresql) to store the content of the messages.

But Adhoc Group Chat is not mentioned to require this external db.

When I try to add a third contact into a one to one conversation, I receive an error message saying it is not supported right now.

The service "XCP Text Conference Manager" was not started. In the Michael's book, it said that this service will fail if there is no external DB configured (for persistent chats), but apparently it works even if there is no ExternalDB configured.